1. Field of the Invention
The present invention relates generally to polyolefin compositions which are capable of being degraded upon exposure to light. More particularly, the present invention relates to polyolefin compositions which are degraded upon exposure to visible or ultraviolet light, said compositions comprising in addition to a polyolefin an aryl substituted 1,3-dione.
2. Description of the Prior Art
Polyolefins and copolymers thereof have previously been used as packaging materials and in agricultural applications, the latter including, for example, mulching films and seed tapes. It is known that these polymers undergo degradation and become fragile when exposed, for prolonged periods of time, to sunlight or other forms of ultraviolet radiation and, for many applications, radiation absorbing agents are added to the polymers in order to stabilize said materials and retard such aging. However, for many other applications, particularly those mentioned above, it is desirable to accelerate the aging of the film. This is particularly true in applications such as mulching films used in agriculture and horticulture and in disposable packaging applications such as films, bags, bottles, hollow articles, and cellulose sheet materials such as paper, cardboard, or regenerated cellulose which are coated or lined with polyolefins.
A variety of additives have previously been suggested for incorporation in polyolefin materials to accelerate the degradation thereof. However, to be useful on a practical, commercial scale the additive must result in a polyolefin composition having sufficient stability for its intended use as well as the capability of degrading in a reasonable period of time after use.